Exploring the Bombardment History of the Moon
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Lunar Impact Crater Identification and Age Estimation with Chang’E
ARTICLE https://doi.org/10.1038/s41467-020-20215-y OPEN Lunar impact crater identification and age estimation with Chang’E data by deep and transfer learning ✉ Chen Yang 1,2 , Haishi Zhao 3, Lorenzo Bruzzone4, Jon Atli Benediktsson 5, Yanchun Liang3, Bin Liu 2, ✉ ✉ Xingguo Zeng 2, Renchu Guan 3 , Chunlai Li 2 & Ziyuan Ouyang1,2 1234567890():,; Impact craters, which can be considered the lunar equivalent of fossils, are the most dominant lunar surface features and record the history of the Solar System. We address the problem of automatic crater detection and age estimation. From initially small numbers of recognized craters and dated craters, i.e., 7895 and 1411, respectively, we progressively identify new craters and estimate their ages with Chang’E data and stratigraphic information by transfer learning using deep neural networks. This results in the identification of 109,956 new craters, which is more than a dozen times greater than the initial number of recognized craters. The formation systems of 18,996 newly detected craters larger than 8 km are esti- mated. Here, a new lunar crater database for the mid- and low-latitude regions of the Moon is derived and distributed to the planetary community together with the related data analysis. 1 College of Earth Sciences, Jilin University, 130061 Changchun, China. 2 Key Laboratory of Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, 100101 Beijing, China. 3 Key Laboratory of Symbol Computation and Knowledge Engineering of Ministry of Education, College of Computer Science and Technology, Jilin University, 130012 Changchun, China. 4 Department of Information Engineering and Computer ✉ Science, University of Trento, I-38122 Trento, Italy. -
Bombardment History of the Moon: What We Think We Know and What We Don’T Know Donald Bogard, ARES-KR, NASA-JSC, Houston, TX 77058 ([email protected])
Planetary Chronology Workshop 2006 6001.pdf Bombardment History of the Moon: What We Think We Know and What We Don’t Know Donald Bogard, ARES-KR, NASA-JSC, Houston, TX 77058 ([email protected]) Summary. The absolute impact history of and 14 soils show a decrease in the number of the moon and inner solar system can in principle beads with age from ~4 Gyr ago to ~0.4 Gyr ago, be derived from the statistics of radiometric ages followed by a significant increase in beads with of shock-heated planetary samples (lunar or age <0.4 Gyr (2). These authors concluded that meteoritic), from the formation ages of specific the projectile flux had decreased over time, impact craters on the moon or Earth; and from followed by a significant flux increase more age-dating samples representing geologic surface recently. However, this data set has also been units on the moon (or Mars) for which crater interpreted to represent variable rates of impact densities have been determined. This impact melt production as a function of regolith maturity history, however, is still poorly defined. (3). In another study, measured ages of 21 small The heavily cratered surface of the moon is a impact melt clasts in four lunar meteorites from testimony to the importance of impact events in the lunar highlands suggested four to six impact the evolution of terrestrial planets and satellites. events over the period ~2.5-4.0 Gyr ago (4). Lunar impacts range in scale from an early Clearly considerable uncertainty exists in the intense flux of large objects that defined the projectile flux over the past ~3.5 Gyr and whether surface geology of the moon, down to recent, this flux has been approximately constant or smaller impacts that continually generate and exhibited appreciable shorter-term variations. -
Timeline of Natural History
Timeline of natural history This timeline of natural history summarizes significant geological and Life timeline Ice Ages biological events from the formation of the 0 — Primates Quater nary Flowers ←Earliest apes Earth to the arrival of modern humans. P Birds h Mammals – Plants Dinosaurs Times are listed in millions of years, or Karo o a n ← Andean Tetrapoda megaanni (Ma). -50 0 — e Arthropods Molluscs r ←Cambrian explosion o ← Cryoge nian Ediacara biota – z ←Earliest animals o ←Earliest plants i Multicellular -1000 — c Contents life ←Sexual reproduction Dating of the Geologic record – P r The earliest Solar System -1500 — o t Precambrian Supereon – e r Eukaryotes Hadean Eon o -2000 — z o Archean Eon i Huron ian – c Eoarchean Era ←Oxygen crisis Paleoarchean Era -2500 — ←Atmospheric oxygen Mesoarchean Era – Photosynthesis Neoarchean Era Pong ola Proterozoic Eon -3000 — A r Paleoproterozoic Era c – h Siderian Period e a Rhyacian Period -3500 — n ←Earliest oxygen Orosirian Period Single-celled – life Statherian Period -4000 — ←Earliest life Mesoproterozoic Era H Calymmian Period a water – d e Ectasian Period a ←Earliest water Stenian Period -4500 — n ←Earth (−4540) (million years ago) Clickable Neoproterozoic Era ( Tonian Period Cryogenian Period Ediacaran Period Phanerozoic Eon Paleozoic Era Cambrian Period Ordovician Period Silurian Period Devonian Period Carboniferous Period Permian Period Mesozoic Era Triassic Period Jurassic Period Cretaceous Period Cenozoic Era Paleogene Period Neogene Period Quaternary Period Etymology of period names References See also External links Dating of the Geologic record The Geologic record is the strata (layers) of rock in the planet's crust and the science of geology is much concerned with the age and origin of all rocks to determine the history and formation of Earth and to understand the forces that have acted upon it. -
TRANSIENT LUNAR PHENOMENA: REGULARITY and REALITY Arlin P
The Astrophysical Journal, 697:1–15, 2009 May 20 doi:10.1088/0004-637X/697/1/1 C 2009. The American Astronomical Society. All rights reserved. Printed in the U.S.A. TRANSIENT LUNAR PHENOMENA: REGULARITY AND REALITY Arlin P. S. Crotts Department of Astronomy, Columbia University, Columbia Astrophysics Laboratory, 550 West 120th Street, New York, NY 10027, USA Received 2007 June 27; accepted 2009 February 20; published 2009 April 30 ABSTRACT Transient lunar phenomena (TLPs) have been reported for centuries, but their nature is largely unsettled, and even their existence as a coherent phenomenon is controversial. Nonetheless, TLP data show regularities in the observations; a key question is whether this structure is imposed by processes tied to the lunar surface, or by terrestrial atmospheric or human observer effects. I interrogate an extensive catalog of TLPs to gauge how human factors determine the distribution of TLP reports. The sample is grouped according to variables which should produce differing results if determining factors involve humans, and not reflecting phenomena tied to the lunar surface. Features dependent on human factors can then be excluded. Regardless of how the sample is split, the results are similar: ∼50% of reports originate from near Aristarchus, ∼16% from Plato, ∼6% from recent, major impacts (Copernicus, Kepler, Tycho, and Aristarchus), plus several at Grimaldi. Mare Crisium produces a robust signal in some cases (however, Crisium is too large for a “feature” as defined). TLP count consistency for these features indicates that ∼80% of these may be real. Some commonly reported sites disappear from the robust averages, including Alphonsus, Ross D, and Gassendi. -
Rare Earth Elements in Planetary Crusts: Insights from Chemically Evolved Igneous Suites on Earth and the Moon
minerals Article Rare Earth Elements in Planetary Crusts: Insights from Chemically Evolved Igneous Suites on Earth and the Moon Claire L. McLeod 1,* and Barry J. Shaulis 2 1 Department of Geology and Environmental Earth Sciences, 203 Shideler Hall, Miami University, Oxford, OH 45056, USA 2 Department of Geosciences, Trace Element and Radiogenic Isotope Lab (TRaIL), University of Arkansas, Fayetteville, AR 72701, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-513-529-9662 Received: 5 July 2018; Accepted: 8 October 2018; Published: 16 October 2018 Abstract: The abundance of the rare earth elements (REEs) in Earth’s crust has become the intense focus of study in recent years due to the increasing societal demand for REEs, their increasing utilization in modern-day technology, and the geopolitics associated with their global distribution. Within the context of chemically evolved igneous suites, 122 REE deposits have been identified as being associated with intrusive dike, granitic pegmatites, carbonatites, and alkaline igneous rocks, including A-type granites and undersaturated rocks. These REE resource minerals are not unlimited and with a 5–10% growth in global demand for REEs per annum, consideration of other potential REE sources and their geological and chemical associations is warranted. The Earth’s moon is a planetary object that underwent silicate-metal differentiation early during its history. Following ~99% solidification of a primordial lunar magma ocean, residual liquids were enriched in potassium, REE, and phosphorus (KREEP). While this reservoir has not been directly sampled, its chemical signature has been identified in several lunar lithologies and the Procellarum KREEP Terrane (PKT) on the lunar nearside has an estimated volume of KREEP-rich lithologies at depth of 2.2 × 108 km3. -
A Zircon U-Pb Study of the Evolution of Lunar KREEP
A zircon U-Pb study of the evolution of lunar KREEP By A.A. Nemchin, R.T. Pidgeon, M.J. Whitehouse, J.P. Vaughan and C. Meyer Abstract SIMS U-Pb analyses show that zircons from breccias from Apollo 14 and Apollo 17 have essentially identical age distributions in the range 4350 to 4200 Ma but, whereas Apollo 14 zircons additionally show ages from 4200 to 3900 Ma, the Apollo 17 samples have no zircons with ages <4200 Ma. The zircon results also show an uneven distribution with distinct peaks of magmatic activity. In explaining these observations we propose that periodic episodes of KREEP magmatism were generated from a primary reservoir of KREEP magma, which contracted over time towards the centre of Procellarum KREEP terrane. Introduction One of the most enigmatic features of the geology of the Moon is the presence of high concentrations of large ion lithophile elements in clasts from breccias from non mare regions. This material, referred to as KREEP (1) from its high levels of K, REE and P, also contains relatively high concentrations of other incompatible elements including Th, U and Zr. Fragments of rocks with KREEP trace element signatures have been identified in samples from all Apollo landing sites (2). The presence of phosphate minerals, such as apatite and merrillite (3); zirconium minerals, such as zircon (4), zirconolite (5) and badelleyite (6), and rare earth minerals such as yttrobetafite (7), are direct expressions of the presence of KREEP. Dickinson and Hess (8) concluded that about 9000 ppm of Zr in basaltic melt is required to saturate it with zircon at about 1100oC (the saturation concentration increases exponentially with increasing temperature). -
Planning a Mission to the Lunar South Pole
Lunar Reconnaissance Orbiter: (Diviner) Audience Planning a Mission to Grades 9-10 the Lunar South Pole Time Recommended 1-2 hours AAAS STANDARDS Learning Objectives: • 12A/H1: Exhibit traits such as curiosity, honesty, open- • Learn about recent discoveries in lunar science. ness, and skepticism when making investigations, and value those traits in others. • Deduce information from various sources of scientific data. • 12E/H4: Insist that the key assumptions and reasoning in • Use critical thinking to compare and evaluate different datasets. any argument—whether one’s own or that of others—be • Participate in team-based decision-making. made explicit; analyze the arguments for flawed assump- • Use logical arguments and supporting information to justify decisions. tions, flawed reasoning, or both; and be critical of the claims if any flaws in the argument are found. • 4A/H3: Increasingly sophisticated technology is used Preparation: to learn about the universe. Visual, radio, and X-ray See teacher procedure for any details. telescopes collect information from across the entire spectrum of electromagnetic waves; computers handle Background Information: data and complicated computations to interpret them; space probes send back data and materials from The Moon’s surface thermal environment is among the most extreme of any remote parts of the solar system; and accelerators give planetary body in the solar system. With no atmosphere to store heat or filter subatomic particles energies that simulate conditions in the Sun’s radiation, midday temperatures on the Moon’s surface can reach the stars and in the early history of the universe before 127°C (hotter than boiling water) whereas at night they can fall as low as stars formed. -
Rare Astronomical Sights and Sounds
Jonathan Powell Rare Astronomical Sights and Sounds The Patrick Moore The Patrick Moore Practical Astronomy Series More information about this series at http://www.springer.com/series/3192 Rare Astronomical Sights and Sounds Jonathan Powell Jonathan Powell Ebbw Vale, United Kingdom ISSN 1431-9756 ISSN 2197-6562 (electronic) The Patrick Moore Practical Astronomy Series ISBN 978-3-319-97700-3 ISBN 978-3-319-97701-0 (eBook) https://doi.org/10.1007/978-3-319-97701-0 Library of Congress Control Number: 2018953700 © Springer Nature Switzerland AG 2018 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. -
Impact Cratering in the Solar System
Impact Cratering in the Solar System Michelle Kirchoff Lunar and Planetary Institute University of Houston - Clear Lake Physics Seminar March 24, 2008 Outline What is an impact crater? Why should we care about impact craters? Inner Solar System Outer Solar System Conclusions Open Questions What is an impact crater? Basically a hole in the ground… Barringer Meteor Crater (Earth) Bessel Crater (Moon) Diameter = 1.2 km Diameter = 16 km Depth = 200 m Depth = 2 km www.lpi.usra.edu What creates an “impact” crater? •Galileo sees circular features on Moon & realizes they are depressions (1610) •In 1600-1800’s many think they are volcanic features: look similar to extinct volcanoes on Earth; some even claim to see volcanic eruptions; space is empty (meteorites not verified until 1819 by Chladni) •G.K. Gilbert (1893) first serious support for lunar craters from impacts (geology and experiments) •On Earth Barringer (Meteor) crater recognized as created by impact by Barringer (1906) •Opik (1916) - impacts are high velocity, thus create circular craters at most impact angles Melosh, 1989 …High-Velocity Impacts! www.lpl.arizona.edu/SIC/impact_cratering/Chicxulub/Animation.gif Physics of Impact Cratering Understand how stress (or shock) waves propagate through material in 3 stages: 1. Contact and Compression 2. Excavation 3. Modification www.psi.edu/explorecraters/background.htm Hugoniot Equations Derived by P.H. Hugoniot (1887) to describe shock fronts using conservation of mass, momentum and energy across the discontinuity. equation (U-up) = oU of state P-Po = oupU E-Eo = (P+Po)(Vo-V)/2 P - pressure U - shock velocity up - particle velocity E - specific internal energy V = 1/specific volume) Understanding Crater Formation laboratory large simulations explosives (1950’s) (1940’s) www.nasa.gov/centers/ames/ numerical simulations (1960’s) www.lanl.gov/ Crater Morphology • Simple • Complex • Central peak/pit • Peak ring www3.imperial.ac. -
March 21–25, 2016
FORTY-SEVENTH LUNAR AND PLANETARY SCIENCE CONFERENCE PROGRAM OF TECHNICAL SESSIONS MARCH 21–25, 2016 The Woodlands Waterway Marriott Hotel and Convention Center The Woodlands, Texas INSTITUTIONAL SUPPORT Universities Space Research Association Lunar and Planetary Institute National Aeronautics and Space Administration CONFERENCE CO-CHAIRS Stephen Mackwell, Lunar and Planetary Institute Eileen Stansbery, NASA Johnson Space Center PROGRAM COMMITTEE CHAIRS David Draper, NASA Johnson Space Center Walter Kiefer, Lunar and Planetary Institute PROGRAM COMMITTEE P. Doug Archer, NASA Johnson Space Center Nicolas LeCorvec, Lunar and Planetary Institute Katherine Bermingham, University of Maryland Yo Matsubara, Smithsonian Institute Janice Bishop, SETI and NASA Ames Research Center Francis McCubbin, NASA Johnson Space Center Jeremy Boyce, University of California, Los Angeles Andrew Needham, Carnegie Institution of Washington Lisa Danielson, NASA Johnson Space Center Lan-Anh Nguyen, NASA Johnson Space Center Deepak Dhingra, University of Idaho Paul Niles, NASA Johnson Space Center Stephen Elardo, Carnegie Institution of Washington Dorothy Oehler, NASA Johnson Space Center Marc Fries, NASA Johnson Space Center D. Alex Patthoff, Jet Propulsion Laboratory Cyrena Goodrich, Lunar and Planetary Institute Elizabeth Rampe, Aerodyne Industries, Jacobs JETS at John Gruener, NASA Johnson Space Center NASA Johnson Space Center Justin Hagerty, U.S. Geological Survey Carol Raymond, Jet Propulsion Laboratory Lindsay Hays, Jet Propulsion Laboratory Paul Schenk, -
Volume 3, Number 3, November 2014
THE STAR THE NEWSLETTER OF THE MOUNT CUBA ASTRONOMICAL GROUP VOL. 3 NUM. 3 CONTACT US AT DAVE GROSKI [email protected] OR HANK BOUCHELLE [email protected] 302-983-7830 OUR PROGRAMS ARE HELD THE SECOND TUESDAY OF EACH MONTH AT 7:30 P.M. UNLESS INDICATED OTHERWISE MOUNT CUBA ASTRONOMICAL OBSERVATORY 1610 HILLSIDE MILL ROAD GREENVILLE DE. FOR DIRECTIONS PLEASE VISIT www.mountcuba.org PLEASE SEND ALL PHOTOS AND ARTICLES TO [email protected] 1 NOVEMBER MEETING TUESDAY THE 11TH 7:30 p.m. OCTOBER MEETING REVIEW: Dave Groski gave a presentation on the Spilhaus Space Clock. This is such an interesting devise that I shall cover it in more detail under the Points of Interest section of the STAR. Dr. Hank Bouchelle once again gave a truly informative talk on not one but several topics related to Astronomy and Physics in general. Since he covered such a varied group of topics, I shall also cover them in the Points of Interest section. Phenomena: Knock! Knock! Is Anyone home? Hank Bouchelle Cinematic depictions of the events accompanying an alien visit are almost uniformly dire. Alien intentions are almost always destructive, deadly, or intended to enslave. They destroy entire populations, and unleash weapons that easily turn Earth to dust. Reports of personal interactions with aliens frequently relate queasy adventures in proctology. It is a bit strange, then, that many people, especially among the scientific community, spare no effort or cost to detect alien messages or the electronic fingerprint of signals that are not produced by the nature. -
Integrated Lunar Transportation System
Integrated Lunar Transportation System Jerome Pearson1, John C. Oldson2, Eugene M. Levin3, and Harry Wykes4 Star Technology and Research, Inc., Mount Pleasant, SC, 29466 An integrated transportation system is proposed from the lunar poles to Earth orbit, using solar-powered electric vehicles on lunar tramways, highways, and a lunar space elevator. The system could transport large amounts of lunar resources to Earth orbit for construction, radiation shielding, and propellant depots, and could supply lunar equatorial, polar, and mining bases with manufactured items. We present a system for lunar surface transport using “cars, trucks, and trains,” and the infrastructure of “roads, highways, and tramways,” connecting with the lunar space elevator for transport to Earth orbit. The Apollo Lunar Rovers demonstrated a battery- powered range of nearly 50 kilometers, but they also uncovered the problems of lunar dust. For building dustless highways, it appears particularly attractive to create paved roads by using microwaves to sinter lunar dust into a hard surface. For tramways, tall towers can support high- strength ribbons that carry cable cars over the lunar craters; the ribbon might even be fabricated from lunar materials. We address the power and energy storage requirements for lunar transportation vehicles, the design and effectiveness of lunar tramways, and the materials requirements for the support ribbons of lunar tramways and lunar space elevators. 1. Introduction NASA is implementing a plan for a return to the Moon, which will build on and expand the capabilities demonstrated during the Apollo landings. The plan includes long-duration lunar stays, lunar outposts and bases, and exploitation of lunar resources on the Moon and in Earth orbit1.